**Serial Numbers**

Bicycles (except children's bicycles) are almost always required to have a frame or serial number. Many manufacturers use a date-code as part of the serial number. 

> For example, a Brompton uses YYMMXXX as their serial code, so a
> Brompton with a serial number of **1306**123456 was manufactured in 2013.06
> or June 2013

[Surly is another manufacturer][1] who uses date codes, this time in their stamped frame numbers. 

**Manufacturers who don't use date codes**

However, many bicycle manufacturers don't use date codes and so you can't easily decode their serial numbers. Some of these manufacturers will provide their own serial number lookups on their websites. Some of the other ones have been reverse-engineered by their rider communities. The best way to find out is to google "*manufacturername* bicycle serial number date of manufacturer."


[![Trek serial number date of manufacture google][2]][2]


  [1]: https://bicycles.stackexchange.com/a/20440/11160
  [2]: https://i.sstatic.net/5hBhq.png